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/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2020 Facebook */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
struct inner_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
} inner_map1 SEC(".maps"),
inner_map2 SEC(".maps");
struct outer_arr {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 3);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
/* it's possible to use anonymous struct as inner map definition here */
__array(values, struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
/* changing max_entries to 2 will fail during load
* due to incompatibility with inner_map definition */
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
});
} outer_arr SEC(".maps") = {
/* (void *) cast is necessary because we didn't use `struct inner_map`
* in __inner(values, ...)
* Actually, a conscious effort is required to screw up initialization
* of inner map slots, which is a great thing!
*/
.values = { (void *)&inner_map1, 0, (void *)&inner_map2 },
};
struct outer_hash {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 5);
__uint(key_size, sizeof(int));
/* Here everything works flawlessly due to reuse of struct inner_map
* and compiler will complain at the attempt to use non-inner_map
* references below. This is great experience.
*/
__array(values, struct inner_map);
} outer_hash SEC(".maps") = {
.values = {
[0] = &inner_map2,
[4] = &inner_map1,
},
};
int input = 0;
SEC("raw_tp/sys_enter")
int handle__sys_enter(void *ctx)
{
struct inner_map *inner_map;
int key = 0, val;
inner_map = bpf_map_lookup_elem(&outer_arr, &key);
if (!inner_map)
return 1;
val = input;
bpf_map_update_elem(inner_map, &key, &val, 0);
inner_map = bpf_map_lookup_elem(&outer_hash, &key);
if (!inner_map)
return 1;
val = input + 1;
bpf_map_update_elem(inner_map, &key, &val, 0);
return 0;
}
char _license[] SEC("license") = "GPL";
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